My earlier filed patent application Ser. No. 08/068,399, filed on May 28, 1993, was concerned with a carriage assembly which is mounted on a rail for translational movement across a cutting board to cut or trim various material. The rail is mounted for pivotal motion with respect to the cutting board to raise the carriage assembly above the paper sheets to allow for placement of the paper sheets to be cut. A circular blade is mounted in the carriage assembly for rotational motion of the circular blade as it passes over the paper sheets. The carriage assembly is biased to an inoperative position on the rail when not in use. The carriage assembly is pushed down to move the blade into engagement with the stack of paper and then moved across the rail to cut or trim the paper. A self healing pad may be provided beneath the carriage assembly and moved across the rail to cut or trim the paper. The rail assembly provides sufficient structural strength to maintain the carriage assembly in a straight line for up to twelve inches. However, the rail cannot maintain a straight line when cuts of longer length are required.